The dramatic increase of popularity of the Internet has led to a corresponding dramatic rise in the popularity of textual communications such as e-mail and instant messaging. Increasingly, browsing of the World Wide Web of the Internet and textual communications are being performed using reduced keypads such as those found on mobile telephones.
Use of such reduced keypads for entering text in the Roman alphabet is manageable since there are only 26 letters in the Roman alphabet. Accordingly, generally three (3) or four (4) letters are mapped to each of eight (8) numerical keys as can be seen on the vast majority of telephones sold in the United States. By having so few letters associated with each key, multi-tap systems provide reasonable text entry functionality for users of the Roman alphabet. Briefly, multi-tap systems uses a number of repeated presses of a key to disambiguate multiple letters associated with a single key. For example, pressing the “2” key once represents the letter “a”; pressing the “2” key twice represents the letter “b”; pressing the “2” key thrice represents the letter “c”; and pressing the “2” key four (4) times represents the numeral “2.” The number of presses of a particular key is typically delimited with a brief pause. Entering textual data of the Roman alphabet using multi-tap is cumbersome and time-consuming.
By contrast, the written Korean language is composed of symbols called “hanguls” which each represent a syllable of a word. There are roughly 11,000 hanguls in the Korean written language. Mapping all hanguls of the Korean language to a standard mobile telephone keypad would require mapping roughly 1,100 hanguls to each key. Fortunately, some hanguls are used only very infrequently. The KS X 1001:1992 standard includes 2,350 hanguls which generally suffice for the majority of communications in the Korean language. Mapping all hanguls of the KS X 1001:1992 standard to a standard mobile telephone keypad would require mapping more than 200 hanguls to each key. Accoringly, multi-tap is not a reasonable mechanism to enter hanguls using a relatively small keypad.
Direct entry of component parts of hanguls, which are called jamos, is somewhat easier. Jamos are consonant and vowel components of hanguls, and a hangul typically consists of two (2) to four (4) jamos. There are about forty (40) jamos in the Korean language. Mapping all forty (40) jamos to a numerical keypad requires mapping of approximately four (4) jamos to each key. Thus, a four-jamo hangul can require sixteen (16) key presses with appropriately placed pauses to be properly specified using a limited keypad. This is even more cumbersome and time-consuming than entering Roman alphabet text using multi-tap.
It is therefore desirable to provide a system for Korean text input that utilizes relatively few entry keys.